Critical: Vulnerability can be used to run attacker code and install software, requiring no user interaction beyond normal browsing.

High: Vulnerability can be used to gather sensitive data from sites in other windows or inject data or code into those sites, requiring no more than normal browsing actions.

Moderate: Vulnerabilities that would otherwise be High or Critical except they only work in uncommon non-default configurations or require the user to perform complicated and/or unlikely steps.

Low: Minor security vulnerabilities such as Denial of Service attacks, minor data leaks, or spoofs. (Undetectable spoofs of SSL indicia would have "High" impact because those are generally used to steal sensitive data intended for other sites.)

WebGL is enabled by default on Windows and Mac OS X. WebGL support requires an OpenGL-capable graphics card. Support for other graphics cards on Windows (specifically Intel GPUs) and Linux will be coming in a future beta

Certain rendering operations are now hardware-accelerated using Direct3D 9 on Windows XP, Direct3D 10 on Windows Vista and 7, and OpenGL on Mac OS X

Improved web typography using OpenType with support for ligatures, kerning and font variants

Firefox 3.6 is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development since early 2009 and contains many improvements for web developers, add-on developers, and users. This version is also faster and more responsive than previous versions and has been optimized to run on small device operating systems such as Maemo.

Notable Firefox 3.6 features include:

Available in more than 70 languages - get your local version.

Support for a new type of theme called Personas, which allow users to change Firefox's appearance with a single click.

Protection from out-of-date plugins to keep users safer as they browse.

Open, native video can now be displayed full screen and supports poster frames.

Firefox 3.6 Beta is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

(NEW) Changes to how we allow third party software to integrate with Firefox in order to prevent crashes.

(NEW) The ability to run scripts asynchronously to speed up page load times.

More than 80 bug fixes from the last beta to improve performance, stability, security and features.

This beta is available in more than 60 languages - get your local version.

Users can now change their browser's appearance with a single click, with built in support for Personas.

Firefox 3.6 will alert users about out of date plugins to keep them safe.

Open, native video can now be displayed full screen, and supports poster frames.

Firefox 3.6 Beta is built on Mozilla's Gecko 1.9.2 web rendering platform, which has been under development for several months and contains many improvements for web developers, Add-on developers and users. This version is also faster and more responsive than previous versions, and has been optimized to run on small device operating systems such as Windows CE and Maemo.

More than 190 bug fixes from the last beta to improve performance, stability, security and features.

This beta is available in more than 45 languages - get your local version.

Users can now change their browser's appearance with a single click, with built in support for Personas.

Firefox 3.6 will alert users about out of date plugins to keep them safe.

Open, native video can now be displayed full screen, and supports poster frames.

Firefox 3.5 is based on the Gecko 1.9.1 rendering platform, which has been under development for the past year. Firefox 3.5 offers many changes over the previous version, supporting new web technologies, improving performance and ease of use. Some of the notable features are:

Available in more than 70 languages. (Get your local version!)

Support for the HTML5 and elements including native support for Ogg Theora encoded video and Vorbis encoded audio.

Firefox 3.5 Beta 4 is based on the Gecko 1.9.1 rendering platform, which has been under development for the past 10 months. Firefox 3.5 offers many changes over the previous version, supporting new web technologies, improving performance and ease of use, and adding new features for users:

Better performance and stability with the new TraceMonkey JavaScript engine.

The ability to provide Location Aware Browsing using web standards for geolocation.

Support for native JSON, and web worker threads.

Improvements to the Gecko layout engine, including speculative parsing for faster content rendering.

Support for new web technologies such as: HTML5 and elements, downloadable fonts and other new CSS properties, JavaScript query selectors, HTML5 offline data storage for applications, and SVG transforms.

Developers can find out about all the changes and new features at the Mozilla Developer Center.